Note that during upgrade, the installation of the new package is considered to happen before the removal of the old package. Therefore, the order of execution of the scripts during an upgrade is:* %pre from the new package* %post from the new package* %preun from the old package* %postun from the old package The first and only argument passed to these scripts is a number indicating the count of installed packages that have the same name as the current package, as it will be after the current operation is completed:* for a fresh in install: 1 during %pre and %post* for a final removal: 0 during %preun and %postun* for an update: 2 during %pre and %post, and 1 during %preun and %postunScripts may use these values to alter their behaviour (for example, to preserve data or perform conversions during an update).